Signal light

ABSTRACT

An enclosure for a signal light includes an elongated radiation transparent section. An elongated radiation source provides three colors of visible radiation, green, amber and red. The radiation source is electrically controlled for sequentially transmitting the green, amber and red colors through the elongated transparent section to provide signals for traffic control.

[ Feb. 5, 1974 United States Patent [191 Munroe 1 SIGNAL LIGHT 2.518.6338/l950 Perry [75] inventor: Donald M. Munroe, Ithaca, NY. 1 8035975/1931 [73] Assignee: Charles C. Krawczyk, Brighton,

Primary Examiner-John W. Caldwell Assistant Examiner-William M. Wannisky22 Filed: June 29 1971 Attorney, Agent, or Firm-Charles C. Krawczyk [57]ABSTRACT An enclosure for a signal light includes an elongated radiationtransparent section. An elongated radiation source provides three colorsof visible radiation, green, amber and red. The radiation source iselectri- 21 Appl. No.: 157,843

cally controlled for sequentially transmitting the green, amber and redcolors through the elongated transparent section to provide signals fortraffic control.

, mmmm 053 /4-D/O.. 0 0 7 4 0 7 3 3 2 s un H 9 ,0 0 H34 4 0; 3 3 2 M4 88 G ,E 7 "33 B moo w WWA 00 n 3 m m m mm u u 8 m m& L Y M W d 5 M U .mFH UN 5 55 References Cited UNITED STATES PATENTS 3,289,629Yarger.............................. 340/84 X 14 Claims, 10 DrawingFigures PAIENTEB EB 5w mmmm INVENTOR. 0. M MON/Q05 SIGNAL LIGHTBACKGROUND OF THE INVENTION This invention pertains to signal lights ingeneral and more particularly to vehicular traffic lights.

The traffic lights presently in use include three separate coloredsignal areas comrising red, amber and green circular lenses arranged ina vertical row. Separate light sources are positioned behind each of thelenses that are individually energized to provide signals for trafficcontrol. The size of such lenses is about eight inches in diameter.Since the size of the lenses is rather small, the range of visibility ofthe signal is limited. Furthermore, such small signal areas have atendency to blend in with other colored background lights, and at timesbecome difficult to observe. This is particularly dangerous in highspeed traffic area wherein drivers need advanced warnings to providesufficient time for safe response.

In addition to the foregoing, ambient light and/or reflection of thesuns rays from the lenses, diminish the effectiveness of such trafficlights by causing all three lenses to appear to be equally illuminated.Depending upon the lighting conditions, time of day, etc., situationsoften arise wherein it is extremely difficult to distinguish which ofthe three signal areas is actually illuminated from those notilluminated. This creates a dangerous situation since a vehicle operatoris required to make a judgement as to the actual condition of thetraftic light. Sun shades have been provided on such traffic lights toreduce the detremental effects of ambient light and reflection of thesuns rays, but were found to be only partially effective.

In a United States Design Patent No. 21 1,837 a trafiic signal casing isillustrated having three horizontally disposed, elongated rectangularshaped red, amber and green signal areas mounted in a verticallydisposed parallel array. The signal areas are intended to be separatelyilluminated with individual light sources in the same manner as thetraffic lights presently in use. The range of visibility of such atraffic signal is greatly extended over the traffic signals presently inuse, however its effectiveness is still diminished by ambient light andreflection of the suns rays. Hence, such an arrangement requiresextensive sun shields to improve the effectiveness of the traffic light.However the ambiguity problem still exists in the traffic light of thedesign patent wherein lighting conditions often exist wherein all threesignal areas appear to be equally illuminated. In addition to theforegoing, the traffic signal of the design patent requires a very largecasing to encompass the three large elongated signal areas. Such a largecasing is highly resistant to winds and thereby exerts large andundesirable forces on its suspension systems. Furthermore, such trafficlights are substantially heavier than the traffic lights presently inuse and therefore can not be readily substituted, particularly in caseswherein the present traffic light is mounted on a cable type suspensionsystem. 7

It is therefore an object of this invention to provide a new andimproved signal light, the effectiveness of which is not diminished byambient light and/or reflection.

It is also an object of this invention to provide a new and improvedtraffic light that is visible at substantially greater distances thanthe traffic lights presently in use.

It is still a further object of the invention to provide a new andimproved signal light having a large signal area and a casing thereforof minimum size, thereby re ducing problems due to storms and wind.

It is also an object of the invention to provide a new and improvedlight weight traffic light having a large signal area that can bemounted on existing traffic light suspension systems.

The signal light of the present invention has a sub stantially greaterrange of visibility than the traffic light in present use, overcomes theproblems due to reflection of the suns rays and ambient light, and is ofa size and weight that it can be readily substituted for the trafticlights presently in use.

BRIEF DESCRIPTION OF THE INVENTION The traffic control colors of thesignal light of the invention are transmitted through a common sectionor signal area of the signal light. Radiation means provides at leasttwo colors of signal radiation for transmission through the commonsignal area. Electrical responsive means sequentially controls thevisible color of the radiation transmitted through the common portion.By using a common area as a changeable color signal source, thedetrimental effects of ambient light are greatly reduced, and theambiguities caused by the reflection of the suns rays is essentiallyeliminated. The visible range of the signal light is increased byproviding a large common signal area, such as for example, in the formof an elongated rectangle.

In a first embodiment of the invention, the radiation means comprises acommon source of radiation and a plurality of movable filters. Theelectrical responsive means sequentially positions the filters betweenthe source and the signal area to control the visible color of theradiation transmitted therethrough.

In a second embodiment of the invention, the radiation means comprises aplurality of separate light sources, filters, and optical means fordirecting filtered light from the sources to the common signal area. Theelectrical responsive means individually energizes the radiation sourcesto control the visible color of the radiation transmitted through thesignal area.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is an isometric view of a casingfor the signal light of the invention.

FIG. 2 is a side view of the signal light of FIG. 1, including a secondsignal area and a second sun shade, and including the radiation sourcesand color cylinder of a first embodiment of the invention in phantom.

FIG. 3 is an isometric view of the color cylinder of FIG. 2.

FIG. 4 is a front view of the signal light of FIG. 1 with the frontpanel removed and color cylinder shown in phantom.

FIG. 5 is a sectional view of FIG. 4 taken along lines 5 5.

FIG. 6 illustrates indicia for the color cylinder of FIG. 3

energizing the light sources and driving the color cylinder of the firstembodiment of the invention.

FIG. 7 is a schematic diagram of a control circuit for FIG. 8 is aschematic diagram of a triac circuit that can be substituted for therelay portion of circuit FIG. 7.

FIG. 9 is a side view of a second embodiment of the signal light of theinvention.

FIG. 10 is a second embodiment of a casing for the signal light of theinvention including indicia in the front panel.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The traffic light of theinvention includes a common, changeable color, signal area for eachdirection of traffic control. In the embodiment of FIG. 1, the signalarea comprises a clear window 10. The window 10 has a generallyelongated rectangular shape, and by way of example, can be six feet longand eight inches high. The window 10 is weatherproof mounted in anelongated rectangular shaped housing 12. A sun shade or visor 14surrounds the window 10. Although the traffic light in FIG. 1 includes asingle window, the traffic light could include a second window 16 and asecond visor 18 (as illustrated in phantom in FIG. 2) on the sideopposite window 10 so that the same traffic light can control oppositedirections of traffic.

In a first embodiment of the invention, the traffic light includes fourfluorescent lights 20 26 mounted in a vertical row (FIGS. 2 & 4). If asingle window is to be used, reflectors 30 36 can be mounted behind thefluorescent lights to reflect the radiation in the direction of thewindow 10. The reflectors 30 36 can also function as grounding strips toaid in starting the lamps. If the traffic light is to use two windowsfor opposite lanes of traffic, the reflectors 30 36 can be eliminatedand the metal strips 40, 42 and 44, extending along the length of thefluorescent tubes and adjacent thereto, can be used as the groundingstrips, as illustrated in FIG. 4.

A color cylinder 48 is mounted to surround and rotate around thefluorescent lamps 20 26. The color cylinder is divided into 66 sectors50 60. The sectors 50 and 56, 52 and 58, and 54 and 60 comprise filtersdesigned to transmit red, amber and green radiation, respectively. Theends of the filter sectors 50 60 are mounted on to the circular mountingdiscs 62 and 64 by a simple disconnect arrangement, such as by dzusfasteners 66 or wind nuts, so that the filter sections can be readilyremoved for easy access to the fluorescent lamps.

The circular mounting discs 62 and 64 comprises two similar semicircularportions 70 and 72 (FIG. each including a smooth semicircular bearingsurface 74 in the central portion thereof. Two bearing mounts 76 and 78are fastened to opposite ends of the casing 12. Each bearing mount 76and 78 includes a circular ring type cut-away portion 80 that includes asuitable bearing so that the mounting discs 62 and 64 can be mountedinto the cut-away portion for easy rotation on the bearing mounts. Thesemicircular portions 70 & 72 of the mounting discs 62 and 64 arepositioned in place in the'cut-away 80 and are fastened together by thebolts 82. A bevel gear 84 is suitably fastened to the circular mountingdisc 64 and is coupled by a bevel gear 86 to an electric motor 88. Whenenergized, the motor rotates the color cylinder 48 about the fluorescenttubes 20 26 to position the various filter sections 50 60 between thelamps and the window to control the color of the radiation transmittedthrough the window.

Three reed switches 90, 92 and 94 are mounted adjacent one end of thecolor cylinder 48 and are spaced longitudinally along the colorcylinder. Three pairs of magnets 96, 98 and (only one of each pair areshown in FIG. 3) are positioned along the color cylinder with a spacingtherebetween corresponding to the spacing between the reed switches 90,92 and 94 respectively. A pair of magnets are provided for each color offilter (one for each filter) and each pair follows the same circularpath as the color cylinder 48 is rotated. The magnets 96 correspondingto the green filter, the magnets 98 corresponding to the amber filterand the magnets 100 corresponding to the red filter, actuate the reedswitches 90, 92 and 94 respectively. The combination of the magnets andreed switches provides a switching arrangement for controlling thepositioning of the color cylinder. It is to be understood of course thatother switching arrangements, such as for example cam operated switches,could also be used.

The fluorescent lamps 20 26 are mounted at opposite ends to the bearingmounts 76 and 78 by bayonet type sockets. The wires to the socketsextend through holes 101 and 103 in the bearing mount.

The electrical circuit for energizing the fluorescent lamps 20 26 andcontrollingthe rotational position of the color cylinder 48 isillustrated in FIG. 7. The terminals 102 are adapted to be connected toa conventional traffic control switching system used to control thetraffic signals in present use. The fluorescent lamps 20 26 are rapidstart, high output type lamps. The lamps 20 and 22 are energized by theballast 112 while the lamps 24 and 26 are energized by the ballast 114.The ballasts l12and 114 are conventionally connected between the powerterminals 102 and 110 and the lamps 20 26, to energize the lamps whenthe relay 116 is energized to close the contacts 118 and 120.

The ballasts 112 and 114 are flashing type ballasts that continuouslyapply heating power to the lamp cathodes. The ballasts 112 and 114 alsoapply a high voltage to the lamps to start an energizing arc dischargein each lamp when the relay 116 is energized to apply a short-circuitacross the terminals 120 and 121, and 121 and 122. Whenever the relay116 is energized, all four lamps 20 26 will be energized. The lightsource for the traffic signal is comprised of two pairs of lamps (20 and22, and 24 and 26) connected in duplicate circuits so that if one lampor a ballast fails, the other two lamps will continue to function.

The motor 88 is connected at one end to the terminal 110 and at theother end through the reed switches 90, 92 and 94 to the terminal 104,I06 and 108 respectively. The reed switches 90, 92 and 94 are normallyclosed until a corresponding magnet 96, 98 and 100 moves to a positionadjacent to a reed switch to open the reed switch.

In operation, when an alternating current potential applied to anyone ofthe terminals 104 108, the connected diode (124, 126 and 128) rectifiesthe alternating current to energize the relay 116. A capacitor 130 isconnected across the coil of relay 116 to keep the relay coil energizedduring negative cycles of the rectified alternating current pulses. Whenthe relay 116 is energized, the lamps 20 26 rapidly turn on. Hence, thelamps 20 26 are energized any time an alternating potential is appliedto any of the terminals 104 108.

The motor 88 is energized by applying power to any of the terminal 104,106 and 108 provided the connected reed switch 90 94 is closed. Forexample, if the color cylinder is positioned in the red output posi tion(the red filter 50 or 56 is positioned between the lamps and the windowor in a position where all three reed switches are closed (as in anyintermediate position of the color cylinder between color outputpositions), and power is applied to the terminal 1114, the motor 88 willbe energized through the reed switch 90 to rotate the color cylinder 48until a magnet 96 is moved into position to open the reed switch 90. Theposition of the magnets 96 with respect to the reed switches 90 is suchthat the motor is de-energized when a green filter 54 or 60 is theoutput position. In the same manner when power is applied to theterminal 106, the color cylinder will automatically rotate an amberfilter 52 or 58 to the output position, and when power is applied to theterminal 108, a red filter 50 or 56 is automatically rotated to theoutput position. Hence it can be seen, by selectively applying power tothe terminals 104 108, the visible color of the radiation transmissionthrough the window will be controlled.

The color cylinder is illustrated as having six sections, two green, twored, and two amber, so that the color cylinder can operate in a singleoutput traffic signal of FIG. 1, and also in a dual output trafficsignal of the type illustrated in FIG. 2. The same color filter islocated on opposite sides of the cylinder so that the same signal colorcan be provided for opposite directions of travel by a single trafficlight. It is to be understood of course, that if the color cylinder isto function as a traffic signal for a single direction of travel, thenthe color cylinder only needs three filter sections, one for each signalcolor, red, green and amber. In addition to the foregoing, the relay 116is needed only if it is desirable to provide a flashing signal. Flashingis accomplished by periodically removing and applying power to theselected terminal 104 108. If there is no need for flashing signals, therelay 116 and the diodes 124, 126 and 128 can be eliminated and thecontacts 120, 121 and 122 can be connected together for continuousillumination.

Although a color cylinder is illustrated as a movable filter means tocontrol the visible color transmitted through the common signal area orwindow 10, other types of movable filters could also be used. Forexample, the color filter can comprise a continuous flexible bandincluding three equal lengths of red, amber and green filter material.The band can be mounted to extend longitudinally about the lamps 26 sothat a portion of the filter is always positioned between the lamps andthe window 10. The band can be held in place at opposite ends of thelamps by rollers. One roller can comprise a drive roller and the otheran idle rol-, ler. The magnetic reed switch control circuit of FIG. 7can be used to control the selective positioning of the colored band.

Alternatively, separate rectangular shaped filters can be movablymounted on a separate sliding track for selective movement into positionbetween the lamps 20 26and the window 10. The filters can be sopositioned in place by a rack and pinion motor driven gear arrangement,or by an electromagnetically operated lever mechanism.

The solid state circuit of FIG. 8 can be substituted for the relay 116of FIG. 7 by connecting the terminals of the solid state circuit to theterminals having the same reference numerals in FIG. 7.

A unijunction transistor 140, a resistor 142 and a capacitor 146 areconnected as a relaxation oscillator to apply pulses through atransformer 148 to render the triacs 150 and 152 conductive. A zenerdiode 154, a resistor 142 and a capacitor provide a stable supplyvoltage for the relaxation oscillator circuit. When an alternatingpotential is applied to any of the terminals 104, 106 and 108, rectifiedAC pulses are applied to the zener diode 154 and the relaxationoscillator is tuned on, which turn provides signal pulses to the gatesof the triacs and 152 to render the triacs conductive to turn on thefluorescent lamps 20 26.

Since a common signal area is used for traffic signal control, some sortof provisions may be provided for color-blind drivers. Various indiciacan be provided on the filter means to provide an indication of thecondition of the signal light. For example, in the case of the colorcylinder 48, the words STOP, GO and CARE can be included respectively onthe red, green and amber filters 50 60. The words can be formed of clearportions in the filters so the words clearly stand out. In the casewherein the color cylinder is to be used with the traffic light of FIG.2 to control two directions of traffic, the indicia can be included inthe various filter sections as illustrated in FIG. 6 so that an indiciais provided for both directions of traffic control.

It should be understood, of course, that other forms of indicia can beincluded on the color cylinder to additionally indicate the condition ofthe traffic signal. For example, as illustrated in with with dashedlines in FIG. 6, the red filter section can include two separatedvertical clear bars and 162, the green filter can include a singleelongated horizontal clear bar 166, while the amber filter section wouldnot include any clear portions. In addition to the foregoing a separateindicia can be included on the front panel to provide an indiciacorresponding to the condition of the traffic light, as illustrated inFIG. 10 wherein the words STOP and G0 are formed with red and greenfilter material respectively. In such a case, separate light sourceswill be provided for each indicia that are conventionally energized inaccordance with the condition of the signal area or window 10.Furthermore, the front casing can also include directional arrow typesignals, when required.

In a second'embodiment of the invention illustrated in FIG. 9, threeseparate fluorescent light sources 180, 182 and 184 provide the amber,red and green light respectively. Each light source comprise a pluralityof fluorescent lamps, each connected to be energized by a separateelectrical circuit in a manner similar to that illustrated in FIG. 7,however requiring a single diode and a separate relay for each lightsource. The reflectors 186, 188 and 190 are mounted behind the lamps todirect radiation from the lamps to a common elongated window 192 of thetype illustrated in FIGS. 1 and 10. An amber filter 194 is placed infront of the source 180, a red filter is placed 196 in front of thesource 182 and a green filter 198 is placed in front of the lamp 184.Accordingly, when the sources 180, 182 and 184 are selectivelyenergized, anamber, a red, and a green color, respectively, istransmitted through the window 192. The color control system of FIG. 9can be employed with a traffic light of the type illustrated in FIG. toprovide the added signal for colorblind drivers.

If the embodiment of the invention of FIG. 9 is to be used with a casingof FIG. 2 to control opposite directions of travel, the arrangement ofFIG. 9 can be duplicated to transmit radiation in opposite direction.Alternatively, the reflectors 186, 188 and 190 can be modified to directradiation in opposite directions and a single source for each color canbe used.

In addition to the foregoing, the amber source 180 can be eliminated andthe green and red sources energized simultaneously to produce the ambercolor.

I claim:

1. A traffic signal comprising:

an enlcosure including an elongated radiation transparent section,wherein the elongated dimension of said section is at least two timeslonger than the shortest dimension of said section;

elongated radiation means mounted within said enclosure for providing atleast two visible colors of radiation for transmission through saidtransparent section, and

means responsive to an electrical signal for sequentially controllingthe visible color of radiation to be transmitted through saidtransparent section.

2. A traffic signal as defined in claim 1 wherein:

said elongated radiation means includes an elongated radiation sourceand a plurality of filters mounted for movement between said source andsaid transparent section, and

said means responsive to an electrical signal sequentially moves saidfilters between said source and said transparent section. 3. A trafficsignal as defined in claim 2 wherein: said plurality of filters arerotatably mounted in the form of a cylinder and surround said source,and

said means responsive to an electrical signal sequentially rotates saidfilters into position between said source and said transparent sectionin a step-bystep manner. 4. A traffic signal as defined in claim 1wherein: said elongated radiation means includes a plurality of separateradiation sources, a separate filter for each separate source and meansfor directing radiation from said separate sources through theirrespective filter to said transmitting section, and

said means responsive to an electrical signal includes a circuit forindividially energizing said separate sources.

5. A traffic signal comprising:

an elongated enclosure including an elongated radiation transparentsection; radiation means mounted within said enclosure for providing anelongated source of visible radiation; a filter means for transmittingdifferent ranges of visible radiation wavelengths corresponding to atleast .two different colors;

means for movably mounting said filter means for movements between saidradiation means and said transparent section, and

electrical 'means coupled to said filtersmeans for moving said filtermeans between said radiation means and said transparent section so thatat least two colors of visible radiation can be sequentially transmittedthrough said transparent section.

6. A traffic signal as defined in claim 5 wherein:

said filter means includes indicia that is visible in said transparentsection when positioned between said radiation means and saidtransparent section.

7. A traffic signal as defined in claim 6 wherein:

said indicia transmitts a range of visible radiation wavelengthsdifferent from the portion of said filter means surrounding saidindicia.

8. A traffic signal as defined in claim 7 wherein:

said indicia forms clear portions of said filter means.

9. A traffic signal as defined in claim 5 wherein:

said source of radiation comprises fluorescent lights,

and

said filter means includes at least two filters for transmittingradiation corresponding to red and green visible colors.

10. A traffic signal as defined in claim 5 wherein:

said filter means has a form in the shape of a cylinder and surroundssaid source;

said filter means includes at least two separate filter portions,longitudinally disposed along different portions of said cylinder inparallel with the axis of the cylinder for providing at least twodifferent colors, and

said filter means is mounted to rotate about said axis around saidradiation source.

11. A traffic signal as defined in claim 5 wherein:

said enclosure is formed with two elongated radiation transparentsections with a separate one of said two transparent sections beinglocated on opposite sides of said enclosure for controlling two oppositedirections of traffic, and

said filter means is movably mounted for movement between said sectionsand said radiation source to control the visible color of the radiationtransmitted through said transparent sections.

12. A traffic signal as defined in claim 11 wherein:

said filter means has the form of a cylinder and surrounds at least aportion of said radiation source, and includes at least two separatefilter portions disposed longitudinally along the circumference cylinderfor providing at least two different colors, and

said filter means is mounted to rotate along the axis of the cylinderabout said radiation source.

13. A traffic signal comprising:

an enclosure including a radiation transparent section;

at least two radiation sources mounted within said enclosure fordirecting radiation through said transparent section;

at least two filters for transmitting at least two different colors;

means for mounting one of said filters to control the color of theradiation transmitted from one of said sources through said transparentsection;

means for mounting the other one of said filters to control the color ofradiation transmitted from said other source through said transparentsection, and

electrical means for controlling the energization of said radiationsources so that at least two different colors are sequentiallytransmitted through said transparent section.

14. A traffic signal comprising:

an enclosure including a seperate radiation transparent section onopposite sides thereof for controlling two opposite directions oftraffic;

radiation means mounted within said enclosure for providing at least twovisible colors of radiation for transmission through said transparentsections, and

means responsive to an electrical signal for sequentially controllingthe visible color of radiation to be transmitted through saidtransparent sections.

1. A traffic signal comprising: an enlcosure including an elongatedradiation transparent section, wherein the elongated dimension of saidsection is at least two times longer than the shortest dimension of saidsection; elongated radiation means mounted within said enclosure forproviding at least two visible colors of radiation for transmissionthrough said transparent section, and means responsive to an electricalsignal for sequentially controlling the visible color of radiation to betransmitted through said transparent section.
 2. A traffic signal asdefined in claim 1 wherein: said elongated radiation means includes anelongated radiation source and a plurality of filters mounted formovement between said source and said transparent section, and saidmeans responsive to an electrical signal sequentially moves said filtersbetween said source and said transparent section.
 3. A traffic signal asdefined in claim 2 wherein: said plurality of filters are rotatablymounted in the form of a cylinder and surround said source, and saidmeans responsive to an electrical signal sequentially rotates saidfilters into position between said source and said transparent sectionin a step-by-step manner.
 4. A traffic signal as defined in claim 1wherein: said elongated radiation means includes a plurality of separateradiation sources, a separate filter for each separate source and meansfor directing radiation from said separate sources through theirrespective filter to said transmitting section, and said meansresponsive to an electrical signal includes a circuit for individiallyenergizing said separate sources.
 5. A traffic signal comprising: anelongated enclosure including an elongated radiation transparentsection; radiation means mounted within said enclosure for providing anelongated source of visible radiation; a filter means for transmittingdifferEnt ranges of visible radiation wavelengths corresponding to atleast two different colors; means for movably mounting said filter meansfor movements between said radiation means and said transparent section,and electrical means coupled to said filters means for moving saidfilter means between said radiation means and said transparent sectionso that at least two colors of visible radiation can be sequentiallytransmitted through said transparent section.
 6. A traffic signal asdefined in claim 5 wherein: said filter means includes indicia that isvisible in said transparent section when positioned between saidradiation means and said transparent section.
 7. A traffic signal asdefined in claim 6 wherein: said indicia transmitts a range of visibleradiation wavelengths different from the portion of said filter meanssurrounding said indicia.
 8. A traffic signal as defined in claim 7wherein: said indicia forms clear portions of said filter means.
 9. Atraffic signal as defined in claim 5 wherein: said source of radiationcomprises fluorescent lights, and said filter means includes at leasttwo filters for transmitting radiation corresponding to red and greenvisible colors.
 10. A traffic signal as defined in claim 5 wherein: saidfilter means has a form in the shape of a cylinder and surrounds saidsource; said filter means includes at least two separate filterportions, longitudinally disposed along different portions of saidcylinder in parallel with the axis of the cylinder for providing atleast two different colors, and said filter means is mounted to rotateabout said axis around said radiation source.
 11. A traffic signal asdefined in claim 5 wherein: said enclosure is formed with two elongatedradiation transparent sections with a separate one of said twotransparent sections being located on opposite sides of said enclosurefor controlling two opposite directions of traffic, and said filtermeans is movably mounted for movement between said sections and saidradiation source to control the visible color of the radiationtransmitted through said transparent sections.
 12. A traffic signal asdefined in claim 11 wherein: said filter means has the form of acylinder and surrounds at least a portion of said radiation source, andincludes at least two separate filter portions disposed longitudinallyalong the circumference cylinder for providing at least two differentcolors, and said filter means is mounted to rotate along the axis of thecylinder about said radiation source.
 13. A traffic signal comprising:an enclosure including a radiation transparent section; at least tworadiation sources mounted within said enclosure for directing radiationthrough said transparent section; at least two filters for transmittingat least two different colors; means for mounting one of said filters tocontrol the color of the radiation transmitted from one of said sourcesthrough said transparent section; means for mounting the other one ofsaid filters to control the color of radiation transmitted from saidother source through said transparent section, and electrical means forcontrolling the energization of said radiation sources so that at leasttwo different colors are sequentially transmitted through saidtransparent section.
 14. A traffic signal comprising: an enclosureincluding a seperate radiation transparent section on opposite sidesthereof for controlling two opposite directions of traffic; radiationmeans mounted within said enclosure for providing at least two visiblecolors of radiation for transmission through said transparent sections,and means responsive to an electrical signal for sequentiallycontrolling the visible color of radiation to be transmitted throughsaid transparent sections.